Diagnosis and syntaxonomic interpretation of Annex I Habitats (Dir. 92/43/EEC) in Italy at the alliance level

Starting from the recently produced Italian Habitats interpretation Manual (http://vnr.unipg.it/habitat), a thorough diagnosis of the Annex I Habitats
recorded in the Italian territory is reported, selecting the alliance level as the most suitable standard phytosociological rank for a detailed nationwide
overview. In order to solve a number of well-known problems, arising from the definitions reported in the European EUR/27 Manual, each Habitat
has been assigned a short, exhaustive although concise diagnostic sentences which contains its most significant ecologic features, with specific
reference to the peculiarities of the Italian territory. Biogeographic, synecological (mainly bioclimatic, morphological, geologic/edaphic), structural
and floristic characteristics of each Habitat are pointed out. When the rarity or vulnerability status has been considered worthy of priority at the
national scale, it has been indicated.
The 131 Habitats listed for Italy, which represent only partially the Italian biodiversity, have been referred to 268 alliances. A complete syntaxonomic
framework is reported in order to offer a robust although still improvable phytosociological ground. The paper aims at standing as a reference
document for Natura 2000 knowledge and management in Italy; it also represents a large-scale, expert-revised tool to allow supra-national
comparisons and support future implementation of the Annex I.